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ROBERT CHARLES MENZIES, OF MUS SELBURGH, COUNTY OF EDINBURGH,

SCOTLAND.

MANUFACTURE OF PAPER FOR CHECKS, 80C.

EBPECIPICATION forming part of Letters Patent No. 302,758, dated July 29, 188%. I Application filed June 26, 1884. (No specimens.) Patented in England May 1!), 1880, No. 2,029.

T0 at whom it may concern.-

Be it known that I, Romsn'r Orrilnnns MEN- arts, of lllusselburgh, in the county of Edinburgh, Scotland, have invented a certain new and useful Improvement in the Manufacture of Paper for Checks and Like Documents, of which the following is a specification.

The object of my invention is to provide paper for checks, monetary, and other valuable documents, so prepared or manufactured that detection of falsification is rendered easy, the alteration of any written or printed matter thereon by the acids, bleach liquor, or alkalies usually employed at once giving a distinct stain. For this purpose I add to the paper at any convenient stage in the manufacture a mixture of iodide and iodate of potassium, starch, and carbonate or sulphate of manganese, and carbonate or sulphate of lead. The proportions of these agents may be va ried; but I have found the following to answer well: potassium iodide, three-fourths of one per cent. in finished paper; potassium iodatc, three-fourths of one per cent. in finished paper; starch, one per cent. in finished paper; sulphate or carbonate of manganese, two per cent. in finished paper; carbonate or sulphate oflead, two per cent. in finished paper.

Manufactured paper may be treated under my invention as follows: The paper, eitherin the web or in sheets, may be dipped into a so lution of the above agents, or may be coated or soaked with the sameby means of a brush.

The iodide and iodate of potassium are for the purposes above mentioned the agents of greatest moment, and are of my invention. They may be employed with other substances than those above mentioucdfor instance, gallic acid can beused in place of sulphate or carbonate of manganese, and in combination with the agents above mentioned without earbonate or sulphate of lead.

Having now set forth the nature and par IVitn esses:

OSCAR IYIAL'MROS, H. G. PEAOOCK. 

